Process of forming laminated tubes.



W. H. KEMPTON.

PROCESS OF FORMING LAMIN:ATED TUBES. APPLICATION. FILED JAN. 5.IBM-RENEWED 00L 2. 1918.

1,284,706. Patented N0v. 12,1918h WITNESSES: g I INVENTOR 1 n fl/moa KSma/an.

fm BY 2 ATTORNEY UNITED STATES PATENT OFFIGE.

WILLARD H. KEMP'I'ON, 0F WILKINSIBURG, PENNSYLVANIA, ASSIGNOR T0 'WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN-SYLVANIA.

PROCESS OF FORMING LAMINATED TUBES.

Application filed January 5, 1915, Serial No. 611. Renewed October 2,1918. Serial- No. 256,625.

To all whom it may concern:

Be it known that I, WILLARD H. KEMP- TON, a citizen of the UnitedStates, and a resident of Wilkinsburg, in the county of Allegheny andStateof Pennsylvania, have invented a new and useful ImprovementinProcesses of Forming Laminated Tubes, of which the following is aspecification.

My invention relates toa process of manu facturing insulating tubes fromabsorbent sheet material, combined, in layers, with a phenoliccondensation product, such as bakelite or condensite, or'with some otheradhesive substance which is adapted to be hardened by the influence ofheat and pressure.

By means of my process, it is possible to produce, in a simple, rapidand effective manner, tubes of high insulating quality having uniformlycompact walls of which the laminated quality has practically disap}peared, the combination being merged intp an integral and homogeneoussubstance. This process is, moreover, carried out with simple andefiicient apparatus and with a minimum of labor.

In the electric arts, much use is made of tubes formed by winding upon amandrel a web of paper or other absorbent material that has been treatedwith a phenolic condensation product or some other adhesive substancewhich may be hardened by the ap-- plication of heat and pressure. Whencylindrical tubes are required, they are completed by subjecting them,while upon the mandrel, to the simultaneous action of pressure and heat.On account of the simultaneous application ofboth heat and consider ablepressure during the winding operation, this process has been very slow,laborious and costly, and the tubes have, to a considerable degree,retained their laminated quality, theirstructure not being as compact,as desirable nor of an integral or homogeneous.

character. When tubes of rectangular or of some other non-circularcross-section are desired, ithas heretofore been usual to remove themfrom the mandrels before they have been heated suficiently to harden theadhesive material, so that they will readily soften when heated again.-The resulting tubes have then been cut into proper lengths,

have then been placed in a heated chamber.

and maintained under superatmospheric pressure for the purpose ofhardening the adhesive material and thus giving the tubes their finalform. In spite of the high air pressure maintained in the heatingchamber, the sides of the tubes have often been blistered and splitapart, and even when the sides of thetubes do not split or blister,their walls are much less compact and ,conerent than those of tubesfinished upon cylindrical mandrels. This results from the fact that,when tubes are heated upon cylindrical mandrels under pressure, there isequal pressure toward the center on all sides of the tubes, while, whentubes are heated upon angular mandrels, the pressure at the corners ismuch greater than thepressure upon the flat sides.

According to my present invention, I modify the process just describedby placing the mandrel carrying a softened tube in a special pressequipped with a pair of heated gether to compress the mandrel and thetubetightly between them, and the form of the platens is such thatpressure is broughtto PatentedNov. 12, 1918. r

bear upon all .sides of'the tubes at once."

Heat is then applied to the platens and a high temperature is maintaineduntil the adhesive material of the tube is thoroughly hardened. Thus,substantially uniform pressure and heat are applied to all points on thesurface of the tube while it is supported throughout its entire area bymeans of the mandrel. rupted and the platens are preferably suppliedwith cooling fluid in order to cool the tube and mandrel, after whichthe finished tube is removed from the mandrel.

In the accompanying drawing, I have not considered it necessary to showthe winding process, as the winding under compres: sion may be carriedout in any convenient The heat isv then i.nter-.

and rapid manner. With respect to the clamping or molding operation, Ishow, in. Figure 1, a side view, partly in elevation and partly insection, of a press adapted for use in practising my process in makingsquare or rectangular tubes. Fig. 2 is a side View, similar to Fig. 1,showing a press having a modified form of platen structure, and Fig. 3is a transverse sectional view of a pair of platens adapted to formcylindrical tubes.

In Fig. 1, a pair of cooperating pressure members 1 and 2 are adapted tobe moved toward and from each other by convenient mechanism. Disposedbetween the'pressure members 1 and 2 are a pair of cotiperating platens3 and t which are designed to form rectangular tubes. The platen 8 isprovided with work-engaging surfaces 5, which, as shown, areperpendicular to each other but which may have any other angularrelation in accordance with the formto be given to the tubes. The platen4 is similarly provided with 'angularly related workengaging surfaces 6and both of the platens have interior passages 8 through which steam orwater may be circulated to heat or cool the platens. A tube 9 is shownin position to be compressed between the platens 3 and 4:, the tubebeing held upon a mandrel 10 which, as shown, is composed of twoseparable portions 11 and 12. The mandrel may be of any suitablematerial and may be composed of one or more sections, but it ispreferably made collapsible in order to facilitate ready removal fromthe finished tube. In order to accommodate rectangular tubes ofdiiferent sizes and different proportions, spacing plates 13 areprovided, and these plates may be varied in number and lengthinbaccordance with the required shape of the tu e.

The structure shown in Fig. 2 differs from that shown in Fig. 1 in thatthe platens 3 and 4 are not provided with self-contained heating means,but are inclosed between upper and lower hollow plates 14 and 15,through which heating and cooling fluids may be circulated.

In the application of my invention to the manufacture of cylindricaltubes, a pressure device like or similar to that shown in Fig. 3 may beused. This pressure device includes coiiperating platens l4c-and 15provided with interior spaces 16 and 17 for admitting heating andcooling fluids and with curved depressions 18 which correspond, incurvature, to a tube 19 that is held on a mandrel 20. The platen 15 isalso pro vided with upturned sides 21 and 22 having inclined sides 23and 24: directed toward the tube 19. Spacing or wedging members 25 and26 are adapted to be received in the spaces between the inclined sides23 and 2d and the tube 19, and, as shown, these wedges are of such shapethat, when the platens 1e aser/cs In practising my process with theappal ratus shown and described, the mandrel and tube, prepared in themanner described above, are placed between the platens, a suitablenumber of spacing, plates 13 or 25 and 26 of the proper size beingintroduced between the tube and one or more of the platens in order thatall sides of the tubes may be tightly compressed when the platens aremoved together. Pressure is then applied and the platens are heatedsufliciently to effect softening and then hardening of the insulatingadhesive substance, which may be done by introducing steam into theinternal passages of the platens or through the hollow plates 14 or 15,if the structure shown in Fig. 2 is employed. When the hardening processis finished, the steam is turned oft and water may be applied to theplatens until the tube and mandrel are cooled, when they may be removedfrom the preps and the tube slipped from the man- The pressuresdeveloped in my process are much greater than the air pressuresobtainable in the pressure devices heretofore in use for similarpurposes, and the strength and compactness of the finished articles arecorrespondingly increased, as well as the rapidity with which thepressing operation is performed. The steps of my process and thestructural details of the apparatus which T have described may bevariously modified by persons skilled in the art without departing fromthe spirit of my invention, and it is therefore to be understood that myinvention comprehends all such modifications as fall within the scope ofthe appended claims.

it claim as my invention:

1. A process of forming angular tubes that comprises winding upon amandrel a web of absorbent sheet material treated with an adhesivesubstance that is adapted to harden under the influence of heat andpressure, heating the wound material suficiently to soften the saidadhesive substance, and applying heated surfaces under high pressure tothe said material to form the sides of the required angular tube and toharden applying heated surfaces to the sides of the I said formed tubeto harden the said adhesive substance.

3. A process of forming angular tubes that comprises winding upon amandrel a web of absorbent sheet material treated with a phenoliccondensation product, heating the wound material sufliciently to softenthe said adhesive substance and applying heated surfaces under highpressure to the said material to form the sides of the required angulartube and to harden the said adhesive substance.

4. A process of forming angular tubes that comprises winding upon amandrel a Web of absorbent material treated with a phenolic condensationproduct, removing the wound material from the said mandrel, heating theresulting tube sufficiently to soften the said adhesive substance,placing the said tube upon a mandrel of the desired angular form, andapplying heated surfaces to the sides of the said formed tube to hardenthe said condensation product, and finally cooling the said surfaces.

5. The herein-described method of making tubing from sheet material,which consists in winding into a tube a fabric bearing an adhesive,internally supporting the tube throughout its entire internal area,applying a substantially uniform heat to the wound tube at all points,and applying externally an approximately uniform mechanical pressure atevery n[fioint on its external surface for unifor the wall of the tube.

In testimony whereof, I have hereunto subscribed my name this 29th dayof Dec.,

WILLARD H. KEMPTON. Witnesses:

Gonom E. MOGEE, B. B. Hmns.

y compressing

